1 Samuel 20:13

the Lord do so and much more to Jonathan. Jonathan most. solemnly promised that he would immediately inform David in case Saul was favorably disposed toward him. But if it please my father to do thee evil, then I will show it thee and send thee away, that thou mayest go in peace, he would not even entrust the message to a servant, but would come in person to impress his warning upon his friend's mind and to make arrangements for his escape; and the Lord be with thee, as he hath been with my father, a wish which indicates that Jonathan may have guessed the true situation of affairs.